1. Field of the Invention
The present invention relates to a polymerizable composition which can be used for image-forming materials such as three-dimensional phototyping material, holographic material, lithographic printing plate precursor, color proof, photoresist and color filter and photo-setting resin materials such as ink, coating compound and adhesive and a polymerizable compound therefor. More particularly, the present invention relates to a polymerizable composition suitable for a so-called direct plate-making lithographic printing plate precursor which enables direct plate making from digital signal from computer, etc. using various lasers and a polymerizable compound therefor.
2. Related Art
Small-sized high output solid lasers, semiconductor lasers and gas lasers emitting ultraviolet rays, visible light or infrared rays at a wavelength of from 300 nm to 1,200 nm are easily available at present. These lasers are very useful as recording light sources in direct plate making from digital data from computer, etc.
Various recording materials sensitive to these lasers have been studied.
Firstly, examples of materials sensitive to a wavelength of not lower than 760 nm which enable recording using an infrared laser include positive-working recording materials disclosed in U.S. Pat. No. 4,708,925, and acidic catalyst-crosslinkable negative-working recording materials disclosed in JP-A-8-276558.
Secondly, examples of recording materials adapted for ultraviolet rays having a wavelength of from 300 nm to 700 nm or visible light lasers include radical polymerizable negative-working recording materials disclosed in U.S. Pat. No. 2,850,445 and JP-B-44-20189.
On the other hand, shortwave light having a wavelength of not higher than 300 nm and electron ray are important for photoresist materials. In recent years, integrated circuits have gained higher integration degree. In the production of semiconductor substrates for ULSI, it has been necessary to form ultrafine patterns having a line width of not greater than halfmicron. To this end, the recent trend is for more exposing devices for photolithrograpy to be designed to have a shorter wavelength. Thus, far ultraviolet rays and excima laser beam (XeCl, KrF, ArF, etc.) have been studied. Eventually, the formation of ultrafine patterns using electron ray has been studied. In particular, electron ray has been regarded as a promising light source for next-generation pattern formation technique.
The subject common to all these image-forming materials is how much ON-OFF of image can be expanded in the areas irradiated and unirradiated with the aforementioned various energies, that is, accomplishment of high sensitivity and storage stability of image-forming material.
There are many examples of use of high sensitivity photoradical polymerizable composition for the purpose of accomplishing the aforementioned subject. As the main components of the photoradical polymerizable composition there are used a radical polymerizable crosslinking agent and a polymer binder. As such a radical polymerizable crosslinking agent there is normally used a polyfunctional crosslinking agent which has two or more polymerizable groups per molecule to enhance its crosslinking efficiency. It is certain that such a photoradical polymerizable composition has a high sensitivity. However, when allowed to stand at high temperature and humidity, such a photoradical polymerizable composition undergoes crystallization if the crosslinking agent is solid or becomes sticky or surfaces if the crosslinking agent is liquid. It has thus been desired to develop a technique for enhancing further the storage stability of such a photoradical polymerizable composition.
On the other hand, in the case where the aforementioned photoradical polymerizable composition is applied to printing plate precursor, it is necessary that the polymerization-cured material which has been exposed to light have a high strength (long press life). A hydrogen bond interaction as attained by urethane resin has heretofore been employed for the purpose of enhancing strength. However, the use of such a hydrogen bond interaction is disadvantageous in that it reduces the flexibility of the resulting film and inhibits the migration of radicals during polymerization to reduce the sensitivity of the photoradical polymerizable composition.